WARNING
This guidance is under active development by NHS England and content may be added or updated on a regular basis.Profile Design
The HL7 FHIR® standard
The HL7 FHIR® standard creates a common foundation on which a variety of different solutions are implemented. The resources contained in the specification usually require further adaptation to particular health or social care use cases; this adaptation is referred to as "profiling" and the resulting artefacts as "profiles".
General profiling approach
The checklist below was adhered to when developing a draft NHS England profile suitable for progression to Clinical and Technical Assurance.
- Ensure that an England use-case that cannot be implemented using a UK-Core FHIR R4 profile has been established.
- Use any corresponding UK Core FHIR R4 profile as a starting point for each profile, where a UK Core FHIR R4 profile exists, refer to it as a starting point for the NHS England profiling exercise.
Approach to StructureDefinition elements
- Identifiers - Where existing NHS Digital IG profiles have applied slicing and profiling to identifiers, this will be recreated in the NHS England IG profiles, then evaluated during Clinical and Technical assurance.
- Removal of elements - No elements will be removed from the FHIR assets for the NHS England IG profiles during initial profiling prior to Clinical and Technical Assurance.
- Experimental element - The FHIR specification defines the 'StructureDefinition.experimental' element as the following, when set to ‘true’: 'This structure was authored for testing purposes (or education/evaluation/marketing), and is not intended for genuine usage.' (Source: HL7). Currently there is no requirement in the NHSE IG to set the experimental element as ‘true’ or ‘false’, so this field should remain in the default view (undefined).
Naming Convention
The NHSE profile name SHALL follow an agreed format.
The name of a profile consists of a number of name segments, and will be in the form:-
[Base][FHIRAssetName][Specialism]
The segments are defined as follows:-
- Base: (Mandatory) - The base for a profile this will always be England.
- FHIRAssetName: (Mandatory) - The name of the base FHIR Resource..
- Specialism: (Required) - This is only used where there are derived NHSE profiles for a given base resource type.
Note: "Mandatory" means that a segment SHALL be present. "Required" means that a segment SHOULD be present, in this case in the event of there being multiple profiles for one base resource.
The physical file name SHALL be in the format [Base]-[FHIRAssetName]-[Specialism] and SHALL be created in the file XML format.
Metadata Usage
The list below contains the element differences between the HL7 FHIR R4 and NHS England IG.
Base Resource Definitions
View further information about FHIR base resource definitions.
| Element name | Base Cardinality | NHS England IG Cardinality | Type | Definition, Constraints and Notes |
|---|---|---|---|---|
| id | 0..1 | 1..1 | id | In the NHS England IG the format is the following, with the FHIRAssetName and Specialism in PascalCase:England-[FHIRAssetName]. |
StructureDefinition Content
View further information about FHIR Resource StructureDefinition - Content.
| Element name | Base Cardinality | NHS England IG Cardinality | Type | Definition, Constraints and Notes |
|---|---|---|---|---|
| url | 0..1 | 1..1 | uri | In the NHS England IG the format is the following, with the FHIRAssetName and Specialism in PascalCase:https://fhir.nhs.uk/England/StructureDefinition/England-[FHIRAssetName]. |
| identifier | 0..* | 0..0 | Identifier | identifier SHALL NOT be used within the NHS England IG |
| version | 0..1 | 1..1 | string | This will follow the Semantic Versioning standard [major.minor.patch].Further details about internal versioning for NHS England assets are available. |
| name | 0..1 | 1..1 | string | In the NHS England IG the format is PascalCase:England[FHIRAssetName] . |
| title | 0..1 | 1..1 | string | In the NHS England IG the format is Proper Case:England [FHIRAssetName] |
| status | 1..1 | 1..1 | code | For the NHS England IG these are defined as:
|
| date | 0..1 | 1..1 | dateTime | Only the date, without time, is populated in NHS England. |
| publisher | 0..1 | 1..1 | string | For all NHS England Profiles, where the base URL is https://fhir.nhs.uk/England, the name of the publisher will be NHS England. |
| contact | 0..* | 1..* | ContactDetail | See Publisher, Contact & Copyright for details of how this SHALL be populated for all NHS England Profiles, where the base URL is https://fhir.nhs.uk/England. |
| description | 0..1 | 1..1 | markdown | The NHS England IG mandates the use of this element. |
| purpose | 0..1 | 1..1 | markdown | This provides traceability of ''why'' the resource is either needed or ''why'' it is defined as it is. |
| copyright | 0..1 | 1..1 | markdown | All NHS England Profiles SHALL contain the the copyright as listed in Publisher, Contact & Copyright |
| fhirVersion | 0..1 | 1..1 | code | The NHS England IG mandates the use of this element. |
| snapshot | 0..1 | 0..0 | BackboneElement | Snapshots SHALL NOT be used within the NHS England IG |
| differential .element .defaultValue[x] |
0..1 | 0..0 | * | Defining default values creates many difficulties in implementation (e.g. when is a value missing?). For these reasons, default values SHALL NOT be used within the NHS England IG. |